The present disclosure relates to an image display device for displaying an image on a display block such as a liquid crystal display panel. In addition, the present disclosure relates to a method of driving the image display device, an image display program executed by the image display device, and a gradation converter included in the image display device.
A liquid crystal display panel adapted to either monochrome display or color display, an electro luminescence display panel using an electroluminescence of either an inorganic material or an organic material, a plasma display panel or the like is used in a display block of a portable electronic apparatus such as a mobile phone or a personal digital assistance, a personal computer, a television receiver or the like.
When a gradation display ability of a pixel of the display block is low, in a word, when the number of gradations in the pixels is small, a contour line like outline is generated in a gradation portion of an image, and as a result, an image quality is reduced. It is known that in such a case, the image quality is enhanced by using an error diffusion method.
The error diffusion method is such that a weight coefficients are added to plural adjacent pixels, respectively, and in this state, an error generated when multivalued image data, for example, is converted into binary image data (that is, a difference between the multivalued image data and the binary image data) is diffused into the plural adjacent pixels. The error diffusion method, for example, is disclosed in R. W. Floyd and L. Steinberg: An adaptive algorithm for spatial grayscale, Journal of the Society for Information Display Vol. 17, No. 2, pp. 75 to 77, 1976 (Non Patent Document). According to the error diffusion method, it is possible to averagely minimize the error generated between the multivalued original image and a half tone image, for example, binarized. As a result, it is possible to produce the half tone image having the excellent image quality.